This invention relates to an improved system for reliably and effectively restraining cargo during transportation. More particularly, this invention relates to a novel system for securing and restraining undesired movement of boxes, drums, and the like within the interior of an intermodal container in ship cargo holds, placed on flatbed truck trailers, on railroad flatcars, or within the interior of truck trailers, railroad cars and the like.
Most shipments for export, both in the United States and abroad, are placed into either twenty or forty foot long, rectangular, intermodal containers. These containers are fabricated with steel, corrugated sidewalls and are structurally self-supporting and rugged. Several intermodal containers may be stacked on top of each other for transport by sea, rail, or road. Within the containers, drums or boxes hold actual product. Each of these forces has the potential to impart a substantial force on an intermodal container.
When traveling by rail, flatbed rail cars transporting intermodal containers may be made up through a process called humping. In this process, a flatbed rail car is pushed over an elevated section of tracks and then allowed to roll into a switching yard, where the cars are switched to make up train segments. When a car is rolled into a stationary string of cars, the impact causes the couplings to lock together. This impact, however, can also apply a jolt to the cargo of the magnitude of several times the force of gravity. Moreover, during transport, cars are subject to sudden braking forces, run-in and run-out impact over grades, rail vibration, dips in the track, and swaying. When intermodal containers are transported by sea, the cargo therein is subjected to rolling storm forces including: yaw, pitch, heave, sway, and surge. On the highway, intermodal containers and the cargo therein experiences acceleration and centrifugal loads, sudden braking, and vibration.
During transportation, an intermodal container and its cargo are two separate entities for the purposes of motion. The container may be mounted in a ship""s cargo hold, on a flatbed railcar, on a flatbed truck trailer, or the like. The cargo, however, unless secured to the container is free to move within the interior of the intermodal container.
When the container changes direction or speed, the cargo tends to continue along the previously existing path until it contacts an interior wall of the container. Without some type of restraint and/or cushioning system, the cargo builds up considerable momentum, independent of the container. The amount of momentum is equal to the object""s mass multiplied by its velocity. In the case of large cargo loads, even the slightest change in direction, or velocity, can generate substantial momentum. When cargo contacts the interior walls or doors of the container, the force necessary to reduce this momentum to zero is absorbed by the goods. Such forces may result in damage to the cargo, damage to the interior walls or doors of the container, damage to the cargo packaging, and may create dangerous leaks if the cargo is a hazardous material. Accordingly, it is undesirable to permit cargo to gain any momentum independent of the container. This is accomplished by restraining the cargo within the container so that the cargo and the container are essentially united during transport and operationally functioning as one object.
In the past, lading has been secured in the container to eliminate unwanted movement or shifting during transport. The drums, boxes, or other containers have been restrained in several different ways. Primarily, cargo was stabilized by a method of load-locking and lumber bracing. This system involves strategically placing lumber between a loadface and the rear doors of a container. This, however, can be a costly, time consuming, and generally inefficient means of securing a load. In this, the blocking process requires carpenters and is often outsourced to contractors. Accordingly, wood barriers can be time consuming to install and not very cost effective. Still further, wood bracing can be somewhat brittle and subject to failure under an abrupt impact. Moreover, conventional methods of load-locking and lumber bracing simply could not perform some tasks. For example, the most efficient means of filling an intermodal container is eighty fifty-five gallon drums double stacked in a twenty-foot long container. If this is done, however, there are only approximately one to two inches between the loadface and the rear doors. One to two inches is not enough space to put sufficient lumber to brace a load of eighty drums adequately. Consequently, when wood bracing was utilized as a system of restraint, shippers were forced to ship containers that were not filled to capacity, thereby reducing transport efficiency and increasing transportation costs.
Similarly, the Bureau of Explosives has established a standard of review to determine if a particular restraint system is capable of adequately securing hazardous cargo. In certain instances, conventional load-locking and lumber bracing was not able to receive approval to ship hazardous cargo by the Bureau.
Other known means of restraint employed ropes, straps, or stands. Methods appearing in the past have tended to exhibit impaired performance and are often not functionally suitable to restrain loads under even moderate conditions. Consequently, a need exists for securing lading in intermodal containers that is functionally effective, cost-affective, labor-efficient, and able to comply with Department of Transportation and Bureau of Explosives regulations.
At least one method and apparatus for restraining cargo movement which overcomes some of the foregoing limitations is disclosed in U.S. Pat. No. 4,264,251, of common assignment with the subject application. The invention disclosed in that patent comprises sealing strips that are adhered to opposing sidewalls of a container, a strip of bracing material, and an adjoining mechanism used to bind the ends of the strips together into a secure and taut restraint. The disclosure of this patent is hereby incorporated by reference as though set forth at length. Thus, the concept of a strip of material being used as a barrier to restrain cargo or lading is disclosed in the ""251 patent.
In the ""251 patent, material strips were applied in a manner similar to hanging wallpaper, wherein a separate adhesive was applied to the surface where adhesion was desired. Then the retaining strip was applied. In addition to this requirement of a separate adhesive, the systems in the past had problems with weakness at the joints. At the juncture where the strips came together, an opportunity existed for slippage of the joined panels. Moreover, intermodal containers have corrugated walls. These corrugations make applying a restraining strip to a separate adhesive, which may not have an even application, substantially more difficult.
Restraining systems in the past required multiple elements, were difficult to store, were arduous to install, and often required a degree of skilled labor. Systems using straps, nails, anchors, or bolts all require substantial storage space even when not in use. Furthermore, such systems increase the safety risk to the workers restraining the cargo.
Still further, products and procedures used in the past relying on accessories located in the cargo container often were not able to secure a partial load. That is, if the load does not extend to the far rear of the container, the necessary anchors may not be available in an area where they can be used.
The problems suggested in the foregoing are not intended to be exhaustive but rather are among many which may tend to reduce the effectiveness of cargo restraining systems. Other noteworthy problems may also exist; however, those presented above should be sufficient to demonstrate that cargo-restraining systems appearing in the prior art have not been altogether satisfactory.
It is a general object of the subject invention to secure a load within a transport container such as a truck trailer, boxcar, intermodal container, or the like which will obviate or minimize problems of the type previously discussed.
It is another object of the subject invention to reduce the material and labor costs involved in securing a load within an intermodal container.
It is still another object of the subject invention to protect cargo from damage during transport.
It is yet another object of the subject invention to provide a system capable of restraining eighty, fifty-five gallon drums, double stacked, in a twenty-foot intermodal container capable of receiving Department of Transportation and Bureau of Explosives approval.
It is a particular object of the subject invention to provide a system for securing cargo that is entirely self-contained and may be installed quickly, reliably, and efficiently by unskilled labor, even in intermodal containers having corrugated walls.
It is another object of the subject invention to provide for efficient and simple removal of the securing system at a cargo destination.
It is a further object of the subject invention to provide enhanced electricity of a restraint system and decrease the amount of adhesive that is needed in providing a reliable attachment to a container sidewall.
It is still a further object of the subject invention to provide a system for restraining cargo that is able to withstand a wide range of temperatures and levels of humidity to enable use in all climates.
One preferred embodiment of the invention that is intended to accomplish at least some of the foregoing objects comprises a flexible, substrate or strip material that is resistant to axial lengthening when placed in tension under the weight of a cargo load. One side of the strip is at least partially coated with a self-adherent adhesive. A release paper is applied over the adhesive and the strip is suitable to be wound on a core. The adhesive coated end is suitable to be adhered to the side wall of a container and the other end of the strip extends laterally around cargo within the container, and is joined to an opposing strip mounted on the opposite side wall of the container to secure a cargo load. The strip increases in width from the first adhesive side wall engaging section to the second load embracing section.
In use, a length of release paper is peeled away from an adhesive portion of the retaining strip. Next, the adhesive face is self-adhered to an interior side of an intermodal container, transport container, tractor-trailer, boxcar, or the like. The adhesive portion of a second strip is applied to the opposite side of the container and a wider portion of the two strips are wrapped around goods to be contained. The ends of opposing strips, which extend around the rear of the container, are overlapped at a center location. A tensioning tool is used to wind the two lapped ends to draw the opposing strips taut. A release paper is then removed from the overlapped or joint region of the strips. A third, shorter piece of the strip material is then adhered to the exposed adhesive of the opposing strips at the joint. The third shorter strip thus locks the side strips in place with an adhesive-to-adhesive seal and forms a secure load restraining system.